Encouraged by NIH's challenge to enable the $1000 genome, current developments in massively parallel sequencing (MPS) continue to increase throughput and reduce the cost of whole-genome sequencing. Unfortunately, the corresponding sample preparation methodologies now lag behind in throughput and DNA quality, thus slowing the pace of discovery and adoption of sequencing techniques in clinical diagnostics. This proposal's focus is to demonstrate the feasibility of controlled DNA shearing utilizing miniature (<200L sample) very high pressure (up to 400Mpa) single pass discharge under controlled and highly energetic conditions to generate the input sample for future massively parallel sequencing (MPS). The proposed systems build on established hydrodynamic mechanism of fluid shear generated under high differential pressure nozzle flow. Long DNA fragments traversing though the nozzle's high velocity gradient are pulled apart due to intense viscous drag forces. For example, at these high pressures, fluid flow velocity will reach 3 times the speed of sound within a very short transition distance. By varying the control parameters of pressure and flow, back pressure, different levels of fragmentation should be achieved. This fragmentation process is not probabilistic and acts upon every DNA molecule that transits the nozzle. The Phase I proposal is focuses on the optimization of control parameters to achieve desired DNA fragmentation performance, following up on preliminary work already done on several prototypes of the two alternative approaches to nozzle design described herein. Each of these approaches can be multiplexed for high throughput use. During Phase II, we intend to expand our studies into large parallel process demonstration.